Encrypting method, deciphering method and certifying method

Abstract

Predetermined information, correlated with the attribute information of an entity, is used as the secret key for encrypting in the public key cipher system or as the secret key for deciphering the enciphered information, thereby enabling to certify the adequacy of the encrypting or deciphering entity at the destination or source of communication. Also predetermined information, correlated with the attribute information of an entity, is used as the public key for encrypting in the public key cipher system or as the public key for deciphering the encrypted information, thereby enabling to certify the adequacy of the entity at the destination or source of communication, at the encrypting or deciphering side.

What is claimed is:  
     
       1. An encrypting method comprising: 
       a first step, of inputting as a key, predetermined information associated with attribute information of an entity;  
       a second step, of inputting the attribute information of the entity;  
       a third step, of normalizing the attribute information input in said second step to be subject to a comparison processing;  
       a fourth step, of comparing the attribute information normalized in said third step and attribute information obtained based on the key input in said first step; and  
       a fifth step, of, when said fourth step results in the attribute information provided in said third step being identical with the attribute information obtained based on the input key, encrypting information to be communicated by using the key.  
     
     
       2. A method according to  claim 1 , wherein said attribute information of the entity is information indicating a physical feature of said entity. 
     
     
       3. A method according to  claim 1 , wherein said predetermined information is information obtained by applying a predetermined process to said attribute information, thereby reducing an information amount thereof. 
     
     
       4. A method according to  claim 3 , wherein said predetermined process employs a one-directional function. 
     
     
       5. A method according to  claim 3 , wherein said predetermined information and information indicating said predetermined process are recorded in a single recording medium. 
     
     
       6. A method according to  claim 1 , wherein said predetermined information is used as a public key in a public key cipher system. 
     
     
       7. A method according to  claim 6 , wherein said predetermined information is recorded in a portable recording medium and is obtained by reading said medium. 
     
     
       8. A method according to  claim 6 , wherein said entity is an entity at a destination of communication, and the attribute of said entity corresponding to said predetermined information is separately observed and the information obtained by said observation is compared with said predetermined information. 
     
     
       9. A method according to  claim 5 , wherein said predetermined information and information indicating said predetermined process are recorded in a single recording medium, and information obtained by processing the information, obtained by observation, according to the information indicating said predetermined process is compared with said predetermined information. 
     
     
       10. A method according to  claim 1 , wherein said predetermined information is used as a secret key in a public key cipher system. 
     
     
       11. A method according to  claim 10 , wherein said entity is an enciphering entity, and is adapted to operate with a secret key obtained by applying a predetermined process to said attribute information and a public key corresponding to said secret key. 
     
     
       12. A method according to  claim 10 , wherein information corresponding to a public key is recorded in a portable recording medium. 
     
     
       13. A decoding method comprising: 
       a first step, of inputting as a key, predetermined information associated with attribute information of an entity;  
       a second step, of inputting the attribute information of the entity;  
       a third step, of normalizing the attribute information input in said second step to be subjected to a comparison processing;  
       a fourth step, of comparing the attribute information normalized in said third step and attribute information obtained on the key input in said first step; and  
       a fifth step, of, when said fourth step results in the attribute information provided in said third step being identical with the attribute information obtained based on the input key, decoding encrypted information by using the key.  
     
     
       14. A method according to  claim 13 , wherein said attribute information of the entity is information indicating a physical feature of said entity. 
     
     
       15. A method according to  claim 13 , wherein said predetermined information is information obtained by applying a predetermined process to said attribute information, thereby reducing an information amount thereof. 
     
     
       16. A method according to  claim 15 , wherein said predetermined process employs a one-directional function. 
     
     
       17. A method according to  claim 16 , wherein said predetermined information and information indicating said predetermined process are recorded in a single recording medium. 
     
     
       18. A method according to  claim 13 , wherein said predetermined information is used as a public key in a public key cipher system. 
     
     
       19. A method according to  claim 18 , wherein said predetermined information is recorded in a portable recording medium and is obtained by reading said medium. 
     
     
       20. A method according to  claim 19 , wherein said entity is an entity at a source of communication, and the attribute of said entity corresponding to said predetermined information is separately observed and the information obtained by said observation is compared with said predetermined information. 
     
     
       21. A method according to  claim 15 , wherein said predetermined information and information indicating said predetermined process are recorded in a single recording medium, and information obtained by processing the information, obtained by observation, according to the information indicating said predetermined process is compared with said predetermined information. 
     
     
       22. A method according to  claim 13 , wherein said predetermined information is used as a secret key in a public key cipher system. 
     
     
       23. A method according to  claim 22 , wherein said entity is a deciphering entity, and is adapted to operate with a secret key obtained by applying predetermined process to said attribute information and a public key corresponding to said secret key. 
     
     
       24. A method according to  claim 23 , wherein the information corresponding to said public key is recorded in advance in a portable recording medium. 
     
     
       25. A certifying method for judging correspondence between information of an entity by comparing predetermined information, correlated with attribute information of said entity, with attribute information of the entity obtained by separately observing the attribute of said entity, wherein the separately observed attribute information is normalized prior to the comparison. 
     
     
       26. A method according to  claim 25 , wherein said predetermined information is used as a public key in deciphering in a public key cipher system, and said entity is the entity at a source of communication. 
     
     
       27. A method according to  claim 25 , wherein said predetermined information is used as a public key in enciphering in a public key cipher system, and said entity is the entity at a destination of communication. 
     
     
       28. A computer-readable storage medium for storing a program for executing an encrypting method, said encrypting method comprising: 
       a first step, of inputting as a key, predetermined information associated with attribute information of an entity;  
       a second step, of inputting the attribute information of the entity;  
       a third step, of normalizing the attribute information input in said second step to be subject to a comparison processing;  
       a fourth step, of comparing the attribute information normalized in said third step and attribute information obtained based on the key input in said first step; and  
       a fifth step, of, when said fourth step results in attribute information provided in said third step being identical with the attribute information obtained based on the input key, encrypting information to be communicated by using the key.